title: Radiation induces diffusible feeder cell factor(s) that cooperate with ROCK inhibitor to conditionally reprogram and immortalize epithelial cells.
abstract: Both feeder cells and Rho kinase inhibition are required for the conditional reprogramming and immortalization of human epithelial cells. In the present study, we demonstrated that the Rho kinase inhibitor Y-27632, significantly suppresses keratinocyte differentiation and extends life span in serum-containing medium but does not lead to immortalization in the absence of feeder cells. Using Transwell culture plates, we further demonstrated that physical contact between the feeder cells and keratinocytes is not required for inducing immortalization and, more importantly, that irradiation of the feeder cells is required for this induction. Consistent with these experiments, conditioned medium was shown to induce and maintain conditionally immortalized cells, which was accompanied by increased telomerase expression. The activity of conditioned medium directly correlated with radiation-induced apoptosis of the feeder cells. Thus, the induction of conditionally reprogrammed cells is mediated by a combination of Y-27632 and a diffusible factor (or factors) released by apoptotic feeder cells.
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Nancy
authors.initials: N
authors.lastname: Palechor-Ceron
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Suprynowicz
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Geeta
authors.initials: G
authors.lastname: Upadhyay
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Dakic
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Tsion
authors.initials: T
authors.lastname: Minas
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Vera
authors.initials: V
authors.lastname: Simic
authors.affiliation: Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Michael
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia; Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Albanese
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia. Electronic address: schleger@georgetown.edu.
authors.forename: Richard
authors.initials: R
authors.lastname: Schlegel
authors.affiliation: Department of Pathology, Georgetown University Medical Center, Washington, District of Columbia; Center for Cellular Reprogramming, Georgetown University Medical Center, Washington, District of Columbia. Electronic address: xl24@georgetown.edu.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Liu
mesh_terms: D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D002454:Cell Differentiation / Q000528:radiation effects*; D002461:Cell Line, Transformed; D017077:Culture Media, Conditioned / Q000494:pharmacology; D061252:Feeder Cells; D005720:Gamma Rays; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice
chemical_list: D017077:Culture Media, Conditioned; D036341:Intercellular Signaling Peptides and Proteins